As a consequence of the wireless transmission of information, it is nowadays possible to track and monitor people and goods in many different ways. Mobile phones can be located with a certain accuracy on the basis of the signals they transmit. If, on the other hand, a special-purpose locator appliance, e.g. a GPS locator, is in use, location can be performed very accurately.
The tracking of objects and goods is performed most often in a closed system inside a building, e.g. in a library, in a shop and in different warehouses. Transmitters or transmitter-receivers that are small in size can be connected to books, to boxes and to other objects. When a book, a box or another object to which a transmitter is affixed is conveyed through a special identification point, the identification point receives information from the object conveyed past the identification point. Transmitters or transmitter-receivers can be implemented with many different technologies. One prior-art technology uses radio-frequency remote identification (RFID, Radio Frequency Identification), i.e. an RFID identifier. An RFID identifier is a small device, which can be incorporated in a product in the manufacturing phase, or glued to it afterwards e.g. with a sticker. RFID identifiers contain an antenna in order to be able to transmit and receive radio frequency enquiries from an RFID transmitter-receiver. RFID identifiers can be either active, passive or semi-passive. Passive RFID identifiers do not have their own power source. The extremely small electrical current required for operation of the device is induced from the radio frequency scanning arriving in the antenna, by means of which the identifier is able to transmit a response. A semi-passive RFID identifier contains a power source, but not its own transmitter. With an inbuilt power source, however, a greater operating range than a passive identifier is achieved and extended functionality is enabled, including saving information in the identifier's own memory. Active RFID identifiers, for their part, contain a power source, and they can have a longer range, as well as a larger memory, than passive identifiers. They can also record additional information transmitted by a transmitter-receiver.
Prior-art remote identification solutions are related e.g. to the automated maintenance of warehouse inventories, intruder alarms, if a good provided with a remote identifier is conveyed past an identification point without proper payment, etc. In other words, prior-art solutions concentrate on tracking individual objects and on notifying the unauthorized taking of them and do not in any way take a stand on the grouping of different objects and on the movement rights of different objects contained in the group and on tracking mobility.